Gas-turbine



Feb. 19, 195 7 LEDlNFGd 2,782,000

GAS-TURBINE Filed DEC. 29, 1951 INVEN'I'OR; MAX VLEDINEGG United StatesPatent GAS-TURBINE Max Ledinegg, Vienna, Austria, assignor toSimrnering-Graz-Pauker Aktiengesellschaft fiir Maschinem, Kesselund Waggonbau,Vienna, Austria, a company of Austria The invention relates to a devicefor cooling the blades in gas turbines. The cooling is intendedprimarily for blades subjected to high temperature stressing beyond 700C. and is effected in a manner known per se by an evaporating liquid,which is caused to circulate by the action of centrifugal force by meansof longitudinal bores in the blade.

It is known to associate a common cooling system with all blades. It isalso known to associate with each blade a cooler of its own, which isindependent of the others and in which the condensation of the vaporformed in the blade is effected. Thereby it is prevented that the wholecooling liquid may flow out upon the leakage of the cooling system evenof one blade only, which would result in extensive damage by all bladesbecoming red hot. On the contrary, the damage is re stricted to the oneblade concerned. The coolers themselves may'be cooled by a secondarymedium, water or air. Particularly in the case of cooling by air, largepassage cross sections must be provided in the rotor, whereby theconstruction of the whole turbine is rendered more difficult inparticular by the requirement oflarge rotor diameters.

The further development of the invention consists in that each axial rowof blades has associated therewith a heat exchanger, which i independentof the heat exchangers of the other rows of blades- Consequently axialrows of blades can be removed easily together with the heat exchanger.The association of a heat exchanger with an axial row of blades,however, enables also a special construction, which in accordance withthe invention consists in that the heat exchanger associated with eachrow of blades are axially spaced from the blade rings. Therefore it isno longer necessary to conduct the secondary cooling medium axiallythrough the rotor; on the contrary, that medium may be reversed withinor behind the sets of coolers so as to emerge at the same end oltherotor body where his admitted.

In-the accompanying drawings; I

Fig. 1 shows by way of example an embodiment of the invention in anaxial section taken through the upper'half thereof, in the case of airbeing used as a secondary cooling medium,

"Fig. 2 is a fragmentary transverse sectional view illustrating a systemof detachable units according to the present invention on anenlargedscale,

Fig. 3 shows the arrangement in the case of a liquid secondary coolingmedium, particularly water, being used.

In Fig. 1, 1 is the casing of the turbine with the guide blades 5, 2 isthe rotor with the rotor blades 11. The hot gases enter at 3 the bladering formed by the guide and rotor blades, and pass off at 4.

The rotating part is sealed against the casing by the labyrinth packings29. In order to be cooled each rotor blade has passage means includingcentral bores 13-and a larger number of peripheral bores 12, whichcommunicate witheacb other at the blade top. In the cen- Cir 7 2,782,000Patented Feb. 19, 1957 tral bores the cooler cooling medium, of higherspecific gravity, flows outwardly under centrifugal force, i heated orevaporated, and when its specific gravity has thus been reduced themedium is forced inwardly. This cooling cycle does not form part of theinvention but has been described only by way of examplebecause othercooling processes may be used without departing from the scope of theinvention.

' The attachment of the rotor blades to the rotor body is effected bymeans of fir-cone roots 21 engaging the outer slot portions 25a of slots25 in the rotor body. Projecting means 25 in the slot portions 25asecure the rotor blades against radial movement. A conduit means It? issecured to the roots of all rotor blades of each axial row of rotorblades, and is located in the inner slot portion 25b of the respectiveslot 25. Each conduit means it) communicates with the passages 12, 13 inthe rotor blades of the respective row, and with the passage of a heatexchanger 10 which is secured to the tubes having cooling fins and beinginserted with the undercut roots 23 thereof into corresponding axiallyextending grooves 29 which are formed in the cavity 14 of the rotorbody.

The cavity 14 shown in Fig. l is closed by a means 27 provided with aninlet 31 and an outlet 32, respec tively communicating with the inlet 3and the outlet 9 of the stator l, and including a partition 24 extendingto about the center portions of the heat exch'angers 10 so that air canbe circulated as a secondary cooling medium through inlets 8 and 31,cavity 14, and outlets 32 and 9. The arrangement shown in Fig. 3 issimilar,

' and a means 27a is provided in the cavity 14a and has of heatexchangers 10. The end portion of the bolts are threaded into therotor,body as described with reference to Fig. 3.

Thes-tatorfl consists of two halves which are connected to each other bymeans of flanges 35 and bolts 35. This construction is known, and not anobject of the present invention.

It will be understood that each row of rotor blades 11, the conduitmeans 10 associated with therespective row of rotor blades IT, and theheat exchanger 10 secured to the respective conduit means it),constitute a detachable unit which is held by root members 21 and 23 inslot portions 25a of slots 25, and in grooves 29, respectively, in sucha manner that each unit is axially slidable, but secured by theprojecting means 25 against radial movement. Consequently, each unit canbe removed in axial direction, and also mounted in axial directionindependently of the other units.

In. order to remove, or mount, a unit, it is, of course, necessary tofirst detach the respectivestator half, and

to withdraw the means 27 or 27a after removing the 3 bolts 28. Theopened cavities 14 and 14a are easily accessible so that each unit canbe pulled out independently of the other units.

Due to the fact that part of each conduit means 10, and moreparticularly the respective associated heat exchangers 10 are allmounted in the same cavity of the rotor body, it is possible to cool allunits simultaneously by a common secondary cooling medium which icirculated through inlets 31 or 8, outlets 32 or 9, and the respectivecavity 14 of 14a in the rotor body.

I claim:

1. In a gas turbine rotor, in combination, a rotor body having an axisand being formed with a plurality of slots extending in axial directionof said rotor body in the outer surface thereof and with a cavityadapted to receive a secondary cooling medium; a plurality of detachableunits, eachunit mounted in one of said slots slidable in axial directionso as to permit removal and mounting of each unit in axial directionindependently of the other units, each unit including a row of axiallyspaced rotor blades formed with passage means for a coolant, meanssecuring the respective unit to said rotor body against radial movement,and a conduit means secured to the rotor blades of said row of rotorblades and communicating with said passage means in the associated rowof rotor blades so as to permit circulation of a coolant through saidconduit means and the rotor blades of the respective unit independentlyof the other units, a part of said conduit means of each of saiddetachable units being located in said cavity so as to be cooled by saidsecondary cooling medium.

2. In a gas turbine rotor, in combination, a rotor body having an axisand being formed with a plurality of slots extending in axial directionof said rotor body in the outer surface thereof and with a cavityadapted to receive a secondary cooling medium; a plurality of detachableunits, each unit mounted in one of said slots slidable in axialdirection so as to'permit removal and mounting of each unit in axialdirection independently of the other units, each unit including a row ofaxially spaced rotor blades formed with passage means for a coolant,means securing the respective unit to said rotor body against radialmovement, a conduit means secured to the rotor blades of said row ofrotor blades and communicating with said passage means in the associatedrow of rotor blades, and a heat exchanger communicating with saidconduit means so as to permit circulation of a coolant through said heatexchanger, said conduit means and the rotor blades of the respectiveunit independently of the other units, said heat exchangers of saiddetachable units being located in said cavity so as to be cooled by saidsecondary cooling medium.

3. In a gas turbine rotor, in combination, an elongated rotor bodyhaving an axis and being formed with a plurality of slots extending inaxial direction of said rotor body in the outer surface thereof, andwith a cavity located at one end of said rotor body and adapted toreceive a secondary cooling medium, a plurality of detachable units,each unit mounted in one of said slots and slidable in axial directionso as to permit removal and mounting of eachunit in axial directionindependently of the other units, each unit including a row of axiallyspaced rotor blades mounted in the associated slot formed with passagemeans for a coolant, means securing the respective unit to said rotorbody against radial movement, a conduit means secured to the rotorblades of said row of rotor blades and communicating with said passagemean in the associated row of rotor blades, and a heat exchanger spacedin axial direction from said rotor blades and communicating with saidconduit means so as to permit circulation of a coolant through said heatexchanger, said conduit means and the rotor blades of the respectiveunit independently of the other units, said heat exchangers of saiddetachable units 1 4 being located in said cavity so as to be cooled bysaid secondary cooling medium.

4. In a gas turbine rotor, in combination, a rotor body having an axisand being formed with a cavity; a plurality of detachable units, eachunit being mounted on said rotor body slidable in axial direction so asto permit removal and mounting of each unit in axial directionindependently of the other units, each unit including an axiallyextending row of rotor blades formed with passage means for a coolant,means securing the respective unit to said rotor body against radialmovement, and a conduit means secured to said rotor blades of said rowof rotor blades and communicating with said passage means in the rotorblades of the associated row of rotor blades so as to permit circulationof the coolant through said conduit means and through said passage meansin the rotor blades of the respective unit independently of the otherunits, a part of the conduit means of each of said units being locatedin said cavity in said rotor body; and means for circulating a secondarycooling medium in said cavity about said part of the conduit means ofeach unit for cooling said conduit means of all said detachable units.

5. In a gas turbine rotor, in combination, a rotor body having an axisand being formed with a plurality of slots extending in axial directionof said rotor body in the outer surface thereof and with a cavity; aplurality of detachable units, each unit mounted in one of said slotsslidablc in axial direction so as to permit removal and mounting of eachunit in axial direction independently of the other units, each unitincluding an axially extending row of axially spaced rotor blades formedwith passage means for a coolant, means securing the respective unit tosaid rotor body against radial movement, a conduit means secured to therotor blades of said row of rotor blades and communicating with saidpassage means in the rotor blades of the associated row of rotor blades,a heat exchanger secured to the respective conduit means andcommunicating with said conduit means; and means for circulating asecondary cooling medium in said cavity about said heat exchangers ofall said detachable units.

6. In a gas turbine rotor, in combination, a rotor body having an axisand being formed with a plurality of slots extending in axial directionof said rotor body in the outer surface thereof and with a cavity; aplurality of detachable units, each unit mounted in one of said slotsslidablc in axial direction so as to permit removal and mounting of eachunit in axial direction independently of the other units, each unitincluding an axially extending row of axially spaced rotor blades formedwith passage means for a coolant, means securing the respective unit tosaid rotor body against radial movement, a conduit means sccured to therotor blades of said row of rotor blades and communicating with saidpassage means in the rotor blades of the associated row of rotor blades,a heat exchanger secured to the respective conduit means andcommunicating with said conduit means, said heat exchangers being spacedin axial direction from said rotor blades; and means for circulating asecondary cooling medium in said cavity about said heat exchangers ofall'of said detachable units.

7. In a gas turbine rotor, in combination, a rotor body having an axisand being formed with a plurality of slots extending in axial directionof said rotor body in the outer surface thereof, and with a cavityadjacent one end of said rotor body; a plurality of detachable units,each unit mounted in one of said slots slidable in axial direction so asto permit removal and mounting of each unit in axial directionindependently of the other units, each unit including an axiallyextending row of axially spaced rotor blades formed with passage meansfor a coolant, means securing the respective unit to said rotor bodyagainst radial movement, a conduit means secured to the rotor blades ofsaid row of rotor blades and communicating with said passage means inthe rotor blades of the associated row of rotor blades, a heat exchangerlocated in said cavity and being secured to the respective conduit meansand communicating with said conduit means; and cooling means forcirculating a secondary cooling medium through said heat exchangers ofall said detachable units and including an axially extending partitionlocated in said cavity so as to define in said cavity an inlet and anoutlet for guiding said secondary cooling medium in one axial directioninto said cavity and in the opposite axial direction out of said cavityso that said secondary cooling medium is supplied to and discharged fromthe same side of said heat exchangers.

8. In a gas turbine rotor; in combination, a rotor body having an axisand being formed with a plurality of slots extending in axial directionofsaid rotor body in the outer surface thereof, and with a cavitylocated spaced in axial direction from said rotor blades and adjacentone end of said rotor body; a plurality of detachable units, each unitmounted in one of said slots slidable in axial direction so as to permitremoval and mounting of each unit in axial direction independently ofthe other units, each unit including an axially extending row of axiallyspaced rotor blades formed with passage means for a coolant, meanssecuring the respective unit to said rotor body against radial movement,a conduit means secured to the rotor blades of said row of rotor bladesand communicating with said passage means in the rotor blades of theassociated row of rotor blades, a heat exchanger located in said cavityand being secured to the respective conduit means and communicating withsaid conduit means; and

cooling means for circulating a secondary cooling me- References Citedin the file of this patent UNITED STATES PATENTS 2,369,795 Planiol et alFeb. 20, 1945 FOREIGN PATENTS 229,933 Switzerland Feb. 16, 1944 271,742Switzerland Nov. 15, 1950 610,737 Great Britain Oct. 20, 1948 623,841Great Britain May 24, 1949

